Quantification of crystalline phases and measurement of phosphate chain lengths in a mixed phase sample by 31P refocused INADEQUATE MAS NMR

A 31P refocused INADEQUATE NMR pulse sequence has been used to identify the crystalline phases present in a sodium calcium phosphate ceramic. An unidentified calcium phosphate phase was observed, featuring a chain of six crystallographically distinct PO4 tetrahedra, the 31P NMR chemical shifts of which have been identified in the correct sequence along the chain.